Let x0 of type ι be given.
Let x1 of type ι → ι → ο be given.
Let x2 of type ι be given.
Apply unknownprop_6dcb04ae0478121c526d391ecd79d3bc0a122d2859e0d05240c64c5ef2e86108 with
dd3c8.. x0 x1 x2,
x0,
x1,
x2.
Let x3 of type ι → ι → ο be given.
The subproof is completed by applying H0.